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Date: Tue, 31 May 2011 10:04:02 -0400
From: Vivek Goyal <vgoyal@redhat.com>
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Subject: Re: [Qemu-devel] [RFC]QEMU disk I/O limits
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To: Anthony Liguori <aliguori@us.ibm.com>
Cc: kwolf@redhat.com, stefanha@linux.vnet.ibm.com, kvm@vger.kernel.org, guijianfeng@cn.fujitsu.com, qemu-devel@nongnu.org, wuzhy@cn.ibm.com, herbert@gondor.hengli.com.au, Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>, luowenj@cn.ibm.com, zhanx@cn.ibm.com, zhaoyang@cn.ibm.com, llim@redhat.com, Ryan A Harper <raharper@us.ibm.com>

On Tue, May 31, 2011 at 08:50:40AM -0500, Anthony Liguori wrote:
> On 05/31/2011 08:45 AM, Vivek Goyal wrote:
> >On Mon, May 30, 2011 at 01:09:23PM +0800, Zhi Yong Wu wrote:
> >>Hello, all,
> >>
> >>     I have prepared to work on a feature called "Disk I/O limits" for qemu-kvm projeect.
> >>     This feature will enable the user to cap disk I/O amount performed by a VM.It is important for some storage resources to be shared among multi-VMs. As you've known, if some of VMs are doing excessive disk I/O, they will hurt the performance of other VMs.
> >>
> >
> >Hi Zhiyong,
> >
> >Why not use kernel blkio controller for this and why reinvent the wheel
> >and implement the feature again in qemu?
> 
> blkio controller only works for block devices.  It doesn't work when
> using files.

So can't we comeup with something to easily determine which device backs
up this file? Though that will still not work for NFS backed storage
though.

Thanks
Vivek